In this paper the new mass spectrometry (MS) method with electrospray desorption ionization (DESI) is described. The method allows selective analysis of tumour markers in intact tissue samples. By DESI-MS the analysis of marker distribution (mass spectrometry imaging) in tissue sample without complicated sample pretreatment can be realised. DESI is a combination of electrospray and desorption ionization technique which are currently used in MS analysis. We can expect that DESI-MS will be useful analytical tool in molecular medicine and in vivo diagnostics.

        Key words: disease markers, diagnostics, mass spectrometry, desorption electrospray ionization.